1. Field of the Invention
This invention related to a recording and/or reproducing apparatus to be used with an optical disk or the like in which an information including a video signal which has been bandwidth-compressed in a variable length coding manner is recorded on or reproduced from the optical disk or the like.
2. Description of the Prior Art
Apparatus in which a video signal has been digitized and encoded and then recorded on a recording medium are very wellknown. In this case, however, such an apparatus has a so-called fixed-length coding in which a video signal is processed so that the amount of data to be generated in one field or one frame or for a time period of one second becomes constant. This is because in a recording medium (magnetic tape or optical disk), the rotation of either a cylinder having a rotational head, or a disk must be synchronized with the period of the video signal in any form (for example, one turn for one frame), so that the amount of data in a predetermined period is constant, which means that the fixed-length coding is best adapted in such apparatus.
Considered from the viewpoint of improving the bandwidth compression, variable length coding is far superior in efficiency to fixed-length coding.
However, it has previously been considered difficult to record or reproduce information encoded on a tape or optical disk by variable length coding because of the fact that the rotational speed of the cylinder or the optical disk must be controlled in accordance with the amount of code.